Rarely seen, easily avoided, and what to do anyway
Thailand has plenty of snakes. You will almost certainly not see one. They avoid people, they move away long before you arrive, and the overwhelming majority of encounters are a tail disappearing into a hedge.
Gardens, pool surrounds, storm drains and long grass — anywhere quiet with cover and something to eat. They are more active after rain and in the early evening. Hotel grounds and villa gardens are landscaped and busy, which is exactly what snakes dislike.
If someone is bitten: keep them still and calm, keep the bitten limb below heart level, and get to a hospital immediately — call 1669 for an ambulance. Do not cut, do not suck, do not apply a tourniquet, and do not attempt to catch the snake. Photograph it from a distance only if that is safe. Thai hospitals hold antivenom and know exactly what to do.
Use a torch when walking a garden path after dark, wear shoes rather than flip-flops on grass at night, and look before reaching into a shrub or under an outdoor sofa. That is genuinely the whole precaution.
We live here — ask us anything about Hua Hin and you will get the real answer.